Bump babel-jest from 25.2.3 to 25.2.6

Bumps [babel-jest](https://github.com/facebook/jest/tree/HEAD/packages/babel-jest) from 25.2.3 to 25.2.6.
- [Release notes](https://github.com/facebook/jest/releases)
- [Changelog](https://github.com/facebook/jest/blob/master/CHANGELOG.md)
- [Commits](https://github.com/facebook/jest/commits/v25.2.6/packages/babel-jest)

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